Front

A front, in addition to its common dictionary meanings, may specifically refer to:

a weather front, a boundary of two airmasses of different temperatures or densities.
In Oceanography, a boundary between water systems having different characteristics based on salinity and temperature.
a military front, an area where armies are engaged in conflict
a front (Soviet Army), a major military subdivision of the Soviet Army
a front organization or front company
a person who acts as a front for a blacklisted artist
"frontal" can refer to the frontal bone and associated structures
a popular method of accessing the mathematics section of arXiv.